Microtubule biogenesis and control both in a unicellular flagellate and in two in vitro assembly systems will be followed during the course of this investigation. Using specific biochemical probes such as colchicine, vinblastine, IPC, trifluralin, and griseofulvin, as well as physical methods such as cold and hydrostatic pressure, the details of microtubule initiation will be examined in vivo and in vitro. Attempts will also be made isolate and purify the recently revealed, well defined microtubule initiation sites in cells of some unicellular flagellates. In addition the effects of surface specific agents on microtubule assembly will also be examined. Complementing these latter studies the distribution of immunologically tagged surface components will also be followed after experimentally inducing loss and recovery of the asymetric cell shape (by depolymerizing microtubule). Finally, using whole cells and purified cell surfaces isolated from specialized organisms, attempts will be made to characterize biochemically and follow developmentally the complex surface components in cells with highly oriented and stable surface pellicles.